When a NetBotz appliance or SNMP device is deleted from NetBotz Central / StruxureWare Data Center Expert, all associated information for the appliance is purged from the server's database. This means that all historical sensor data, alert data, and surveillance data will be deleted.

Resolution:

There is no workaround at this time. If it is necessary to retain data from a device even if it has ben physically removed, the entry for that device, even though it has no communications, must be left on the system.